Enantioselective synthesis of isotopically labelled L-α-amino acids preparation of 13C-, 18O-and 2H-labelled L-serines and L-threonines
作者:W. F. J. Karstens、H. J. F. F. Berger、E. R. Van Haren、J. Lugtenburg、J. Raap
DOI:10.1002/jlcr.2580361108
日期:1995.11
[3-18O]-L-serine, [3-13C]-L-serine, [3-18O]-L-threonine, [3,4-13C2]-L-threonine and [3-2H]-L-threonine are prepared from simple commercially available, isotopically enriched starting materials like H218O, [13C]-paraformaldehyde, [13C2]-acetaldehyde and [1-2H]-acetaldehyde. The introduction of the side chain is based on the reaction of the anion of the bislactimether of cyclo-(D-Val-Gly) with a suitable reagent. For serine this is isotopically labelled benzylchloromethylether, whereas for threonine labelled acetaldehyde is used in combination with chlorotitaniumtris[diethylamide], introducing both stereocentres in one single step. The isotopomers of serine and threonine are obtained on the gram scale in good yields and high enantiomeric and diasteriomeric excesses. New syntheses for [18O]-benzylalcohol and isotopically enriched benzylchloromethylether are reported. Following the presented synthetic scheme these amino acids can be labelled at any position or at any combination of positions.
[3-18O]-L-丝氨酸、[3-13C]-L-丝氨酸、[3-18O]-L-苏氨酸、[3,4-13C2]-L-苏氨酸和[3-2H]-L-苏氨酸是从简单的商业可得的、同位素富集的起始材料如H218O、[13C]-聚甲醛、[13C2]-乙醛和[1-2H]-乙醛中制备的。侧链的引入基于环(D-Val-Gly)的双内酰胺醚阴离子与适当试剂的反应。对于丝氨酸,使用标记的苄基氯甲基醚,而对于苏氨酸则结合了标记的乙醛和氯化钛三[二乙胺],在一步中引入两个立体中心。丝氨酸和苏氨酸的同位素异构体在克尺度上获得,产率良好,且具有较高的对映体和非对映体过剩。报告了[18O]-苄醇和同位素富集的苄基氯甲基醚的新合成方法。根据所呈现的合成路线,这些氨基酸可以在任意位置上或任意位置组合上进行标记。